How do I get mathematica to consider a parameter in an integrand to be
real.
Example:
In[1]:Integrate[1/(Cos[x] Sqrt[Cos[x]2 - a2]), x]
ArcTanh[(Sqrt[2] Sqrt[-a2] Sin[x])/Sqrt[1 - 2 a2 + Cos[2 x]]]/Sqrt[-
a2]
But I want a2>0 (a real).